Radio fire-alarm system



May 17, 1927. 1,629,337

H. GARRETT RADIO FIRE ALARM SYSTEM Original Filed 0013.14, 1925 y INVEN TOR.

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Patented May 17, 1927. r

UNITED STATES HENRY GARRETT, 01 DALLAS, TEXAS.

RADIO FIRE-ALARM SYSTEM.

Application filed October 14, 1925, Serial 1T0. 62,482. Renewed March 26, 1827.

It is well understood that fire alarm sig nals are transmitted from alarm boxes to the various stations where gongs or other signals are located, local alarm circuits connected to so called repeaters.

The principal object of the present i'nvention' is to provide a novel means for broadcasting the signals received in such stations so that they may be transmitted, without wires, to any receiving stations whether they be located on a moving vehicle such as an automobile or in a stat1onary position.

With the above and other objects in view as will be hereinafter apparent, the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings and specifically claimed.

In the accompanying drawing the figure is a wiring diagram disclosing the invention. Ashore shown the wires lead in from the fire boxes to the magnet 11 of a gong 12 having a hammer 13 forming the armature of the magnet and provided with an arm 14 constituting a circuit closer movin under the influence of the magnet into an out of contact with a fixed contact 15. The pivot of the hammer is connected by a wire 16 with a battery 17, the other terminal of which is connected by a wire 18 with a relay magnet 19. From the contact a wire 20 also leads to said magnet 19 so that opening and closing this circuit actuates the relay controlled by said magnet. Also a key 21 is bridged across the wires 16 and 20 so that the circuit may be controlled manually and independent of the magnet 11.

The wires of the local alarm circuit to the repeaters are shown at 22 and in this circuit is included a relay magnet 23 controlling an armature 24 which normally engages a fixed contact 25 connected by a wire 26 with a relay magnet 27. This magnet is connected by a wire 28' with one terminal of a battery 29 the other terminal of whichis connected by a mm 30 with the armature 24. A key 31 is bridged across wires 26 and.

The magnet 27 controls an armature 32 normally out of engagement with a fixed contact 33 connected by a wire 34 with one of the brushes of an alternating current motor 35 having its other brush connected by a w1re36 with one side of the A. C. circuit.

1,629,337 PATENT' OFFK$13.

The base of this armature connects with the.-

magnet 43 a wire 45 leads to the remaining element of the circuit closer 40.

The magnet 43 controls an armature 46 which is normally out of contact with a fixed contact 47 connected .by a wire 48 with one of the wires 37. The armature 46 is connected by a wire 49 with one brush of an alternating current motor 50 having its other brush connected by a wire 51 with the remaining wire 37. This motor drives a high tension generator 52 having one of its brushes connected by a wire 53 with one terminal of a radio choke coil 64. The other brush of this generator is connected by a wire 55 with the-plate of a three element vacuum tube 56. The'wires 37 are also connected to a step down transformer 57 which feeds the filaments of the tube 56 and a tube 58 through wires 59' one of which is connected to the second brush of the generator 52 by a branch wire 60. A branch wire 61 connects the plate of tube 58 to wire 55. Both grids are connected by a wire 62. A tuning inductance 63 has the middle point of one winding connected by a Wire 64 with a grid leak 65 and one end of this winding is connected to one of the wires 59 while the other end is connected by a wire 65 to the armature 66 of the -magnet 19. A variable condenser 67 is bridged across the terminals a wire 69 through a chopper 70 tocan aerial 71. This chopper is driven by .a motor 72 having one brush connected to the wire 34 and its other brush connected to one of the wires 37; A fixed contact 73 is engageable by the armature 66and is connected by a wire 74 with the wire 55.

The operation is as follows:- 7

When an alarm comes in the relay of the repeater circuit closes a circuit through battery 29 which operates rela magnet 27 to close a power circuit througl i the motors and 72. When the motor 35 reaches proper speed a circuit is closed through the battery 42 which'acts to close the power circuit through the motor thus driving generator 52. Also each breaking and closing of the circuit through wires 18 actuates the relay l9 and thus causes signals to be broad cast from the aerial in accordance with the alarm received. I

Having thus described the invention, what is claimed as new, is:

1. In a fire alarm system an alarm receiving apparatus, a high tension generator, radio transmitting apparatus connected to and fed by said generator and including an antenna circuit, means governed by the alarm receiving apparatus for interrupting the antenna circuit. a motor for.

driving the generator, a normally open local circuit including a relay, a power circuit connected to said motor and closed by said relay, a second local circuit including a relay. and a circuit including a motor and controlled by the last relay, said last circuit controlling through the action of its motor the normally open local circuit.

2. In a fire alarm system, an alarm receiving apparatus, a high tension generator, radio transmitting apparatus connected to and fed by said generator and including an antenna circuit, means governed by the alarm receiving apparatus for interrupting the antenna circuit, a motor for driving the generator. a. first normally open local circuit including a relay, a power circuit connected to said motor and closed by said relay. a setond local circuit; including a relay, and a circuit. including a motor and controlled by the last, relay, said last circuit controlling through the action of its motor the first relay circuit, said last motor act uatopen local circuit.

In a fire alarm system, an alarm receiving apparatus, a high tension generator. radio transmitting apparatus connected to and led by said generator and including an antenna circuit, means governed by the alarm receiving apparatus for controlling the antenna circuit, a motor for driving the generator, a first normally open local circuit including a relay, a power circuit connected to said motor and closed by said relay, a second local circuit including a relay, a circuit including a motor and controlled by the last relay. said last circuit controlling through the action of its motor the first normally open relay circuit, said last motor actuating a governor for closing the first normally open relay circuit, said antenna circuit having a chopper interposed therein. a motor driving said chopper. and means controlled by the second local rir cuit for closing a circuit through the lastmentioned motor.

In testimony whereof I allix my signature.

HENRY GARRETT.

mg a governor for closing the first normally 

